Flower-of-an-Hour (Hibiscus trionum)

Flower-of-an-Hour

Hibiscus trionum

Delicate blooms fade after hours, a fleeting summer charm. Annual flowering herb; common names: Bladder Hibiscus.

Full sun
1–2/week
Beginner
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Plant Needs

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Sunlight Thrives in full sun to partial shade; provide afternoon shade in extreme heat to prevent foliage scorch
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Watering Water deeply when the top 2–3 cm of soil feels dry; avoid overwatering to prevent root rot
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Temperature Prefers warm temperate to subtropical temperatures; cannot tolerate frost and will die back after first cool snaps
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Characteristics

  • Leaf: Palmate 3-lobed leaves with toothed margins and fuzzy, light green texture
  • Flower: White or pale yellow blooms with purple centers, opening for only 2–3 hours daily
  • Fruit: Inflated, papery bladder-like capsule containing small brown seeds
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Care Guide

Watering

Keep soil consistently moist but not waterlogged; increase frequency during heatwaves

Fertilization

Diluted balanced liquid feed every 2 weeks. Cease fertilization once flowering ends to support natural senescence

Banana peel tea:Soak chopped banana peels in water for 24 hours; dilute 1:10 with water for root drenching to support flower production
Pruning
  • Deadhead spent blooms promptly to encourage extended flowering
  • Remove yellowing or damaged foliage to improve airflow and reduce pest habitat
  • Trim leggy mid-summer stems to promote bushier, more compact growth
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Toxicity

Warning: this plant may be toxic.

Pets & Humans

Pets: ASPCA: Toxic; may cause vomiting, diarrhea, and decreased appetite

Humans: Contains hibiscin compounds; ingestion of large amounts may cause mild gastrointestinal upset

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Garden Uses & Culture

Culture: N/A

Usage: Ornamental garden annual; young leaves occasionally used in small quantities in fresh salads